Qantas domestic cabin crew have applied to the federal industrial umpire to take protected action over fatigue concerns and claims of outsourcing.
The Flight Attendants' Association of Australia (FAAA) says Qantas management "have threatened employees that they will not have access to work on new aircraft unless they sign onto new enterprise agreements that dramatically cut conditions".
In May, Qantas ordered 20 Airbus A321XLR aircraft as part of the first tranche of its domestic fleet renewal which will replace its Boeing 737 aircraft.
The association says the airline would extend shifts from 10 to 12 hours for crew on the new Airbuses and cut rest time between shifts.
"To force crew to work even longer and harder than they already are with no additional break between shifts would cause more to go off sick with fatigue, causing further disruption to an already chaotic Qantas flight schedule," said the association's general secretary Teri O'Toole.
But Qantas denies the union's claims, saying the "grounds for taking this step towards industrial action are misleading".
"The shift length changes we're asking for are the same that apply to crew working at other domestic airlines in Australia," a Qantas spokesperson told AAP on Wednesday.
They also denied any plans to outsource the attendants' shifts.
"The FAAA signed off on these conditions as part of agreements for those airlines, so it's bizarre they're now claiming they're unsafe."
If the FAAA's application is successful cabin crew will then vote on industrial action which Qantas says cannot take place before mid-November.
"Cabin crew may serve tea and coffee on a good day, but when it's not a good day at the office they are the firefighters, the paramedics and the police on that aircraft, and they need to be able to act fast and be free of fatigue," Ms O'Toole said.
"Qantas turned a deaf ear to crews' safety concerns and instead issued an ultimatum. This is not good faith bargaining, it's bullying ... despite Qantas being the largest recipient of JobKeeper payments."
However, the airline maintains the deal it is proposing to the union has considerable financial incentives that assuage their concerns.
Last month, Qantas chairman Richard Goyder apologised to customers for the "bumpy" restart to regular travel which has resulted in flight delays and missing baggage.
